There is an error when establishing a meeting between Skype Business (Lync) on-premise and another Skype Business (Lync) on Premise. It does not connect, the conferencing service does not respond.
WSS is intercepting the Skype for Business (Lync) traffic.
Here is a list of the destination URLs that need to be bypassed for Skype for Business (Lync) to work properly.
You can access the SSL exception list by doing the following:
Log in to Portal, then go to Service > SSL interception > SSL interceptions Exemptions, in "Destinations" click "Add" and either input the URLs one by one or import a .txt file.
Press the "Activate" button after having added the domains.
Add Individually or import to portal via txt file.